Routing devices within a network, often referred to as routers, maintain routing information that describes available routes through the network. Upon receiving an incoming packet, the router examines information within the packet and forwards the packet in accordance with the routing information. In order to maintain an accurate representation of the network, routers exchange routing information in accordance with one or more defined routing protocols, such as the Border Gateway Protocol (BGP).
Multi-Protocol Label Switching (MPLS) is a suite of protocols used to engineer traffic patterns within Internet Protocol (IP) networks. By utilizing MPLS, a source device can request a path through a network to a destination device, i.e., a Label Switched Path (LSP). An LSP defines a distinct path through the network to carry MPLS packets from the source device to a destination device. Each router along a LSP allocates a label and propagates the label to the closest upstream router along the path. Routers along the path cooperatively perform MPLS operations to forward the MPLS packets along the established path. A variety of protocols exist for establishing LSPs, such as the Label Distribution Protocol (LDP) and the Resource Reservation Protocol with Traffic Engineering extensions (RSVP-TE).
MPLS protocols such as these have been successful in many types of networks including core service provider networks and wide area networks (WAN). However, applying MPLS protocols in access networks can be difficult because many access networks are arranged as a ring topology. Due to ring topology, path protection mechanisms such as RSVP-TE Fast re-route (FRR) and LDP FRR may be inefficient and complex. Moreover, conventional MPLS protocols are typically not sufficiently flexible nor do they scale well for widespread adoption in ring-based access networks.